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Re: [Qemu-devel] [RFC PATCH] Expose tsc deadline timer feature to guest
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [RFC PATCH] Expose tsc deadline timer feature to guest |
Date: |
Mon, 2 Jul 2012 14:54:00 -0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Jul 02, 2012 at 11:08:14AM +0000, Liu, Jinsong wrote:
> Eduardo, Jan, Andreas
>
> As we sync 3 months ago, I wait until qemu1.1 done, then re-write patch based
> on qemu1.1.
> Now it's time to re-write my patch based on qemu1.1.
>
> Attached is a RFC patch for exposing tsc deadline timer to guest.
> I have checked current qemu1.1 code, and read some emails regarding to cpuid
> exposing these days.
> However, I think I may ignore something (so many discussion :-), so if you
> think anything wrong, please point out to me.
Looks good, considering that even if we change the GET_SUPPORTED_CPUID
behavior eventually, there are existing kernels that use
KVM_CAP_TSC_DEADLINE_TIMER to report TSC-deadline support. So:
Reviewed-by: Eduardo Habkost <address@hidden>
>
> Thanks,
> Jinsong
>
> ====================
> From 8b5b003f6f8834d2d5d71e18bb47b7f089bc4928 Mon Sep 17 00:00:00 2001
> From: Liu, Jinsong <address@hidden>
> Date: Tue, 3 Jul 2012 02:35:10 +0800
> Subject: [PATCH] Expose tsc deadline timer feature to guest
>
> This patch exposes tsc deadline timer feature to guest if
> 1). in-kernel irqchip is used, and
> 2). kvm has emulated tsc deadline timer, and
> 3). user authorize the feature exposing via -cpu or +/- tsc-deadline
>
> Signed-off-by: Liu, Jinsong <address@hidden>
> ---
> target-i386/cpu.h | 1 +
> target-i386/kvm.c | 5 +++++
> 2 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index 79cc640..d1a4a04 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -400,6 +400,7 @@
> #define CPUID_EXT_X2APIC (1 << 21)
> #define CPUID_EXT_MOVBE (1 << 22)
> #define CPUID_EXT_POPCNT (1 << 23)
> +#define CPUID_EXT_TSC_DEADLINE_TIMER (1 << 24)
> #define CPUID_EXT_XSAVE (1 << 26)
> #define CPUID_EXT_OSXSAVE (1 << 27)
> #define CPUID_EXT_HYPERVISOR (1 << 31)
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 0d0d8f6..52b577f 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -361,8 +361,13 @@ int kvm_arch_init_vcpu(CPUX86State *env)
> env->cpuid_features &= kvm_arch_get_supported_cpuid(s, 1, 0, R_EDX);
>
> i = env->cpuid_ext_features & CPUID_EXT_HYPERVISOR;
> + j = env->cpuid_ext_features & CPUID_EXT_TSC_DEADLINE_TIMER;
> env->cpuid_ext_features &= kvm_arch_get_supported_cpuid(s, 1, 0, R_ECX);
> env->cpuid_ext_features |= i;
> + if (j && kvm_irqchip_in_kernel() &&
> + kvm_check_extension(s, KVM_CAP_TSC_DEADLINE_TIMER)) {
> + env->cpuid_ext_features |= CPUID_EXT_TSC_DEADLINE_TIMER;
> + }
>
> env->cpuid_ext2_features &= kvm_arch_get_supported_cpuid(s, 0x80000001,
> 0, R_EDX);
> --
> 1.7.1
--
Eduardo